1. Field of the Invention
The invention relates to an arrangement for recording information signals in recording tracks on a magnetic tape and comprising at least one rotationally drivable magnetic head for scanning inclined recording tracks on the magnetic tape, and a tape drive device for intermittently driving the magnetic tape in a longitudinal direction of the tape, in which, for recording an information signal segment by the magnetic head in an inclined recording track during a recording cycle, the magnetic tape is accelerated from standstill to a given recording tape speed and is subsequently driven at the recording tape speed for at least the duration of the recording of the information signal segment, and is then subsequently braked to standstill, and in which, after completion of a recording cycle, the stationary magnetic tape is scanned by the magnetic head along an inclined reproducing track which partly overlaps the inclined recording track last scanned, and the information signal segment recorded in the inclined recording track last scanned is reproduced.
2. Description of the Related Art
Such an arrangement of the type defined in the opening paragraph is known, for example, from German Patent DE 39 16 379 C3, the known arrangement being a video recorder by means of which so-termed "time-lapse" operation is possible.
A problem encountered with such an arrangement of the type defined in the opening paragraph, is that when braked to standstill, the magnetic tape is tensioned due to mechanical effects and slackens after braking, so that the magnetic tape, particularly in the area scanned by the rotationally drivable magnetic head, moves slightly backward in the longitudinal direction of the tape, as a result of which an inclined recording track, which is subsequently scanned for recording a further information signal segment, such as a video field signal, in the longitudinal direction of the tape, may be situated at a distance from the inclined recording signal track last scanned during the recording of the information signal segment last recorded, this distance not being in conformity with a predetermined nominal value, and depending on the conditions during braking and slackening of the magnetic tape. In particular, said distance also depends on temperature influences, aging influences of the mechanical parts which cooperate with the magnetic tape, such as the tape-drive capstan, tape guides and the like, and humidity influences, as well as on the magnetic tape and a cassette containing the magnetic tape used in each case. Such deviations of the distances between successive inclined recording tracks in the longitudinal direction of the tape from said nominal value, has the drawback that they give rise to disturbances during a subsequent reproduction of the information signal segments recorded in all these inclined recording tracks, which is undesirable.
In order to minimize such deviations of the distances between successive inclined recording tracks in the longitudinal direction, in an arrangement whose tape drive device comprises a motor-driven capstan disposed downstream the rotationally drivable magnetic head in the longitudinal of the tape, for intermittently driving the magnetic tape, against which capstan the magnetic tape can be pressed by means of a tape pressure roller, it is possible to brake the capstan continually by means of a mechanical additional brake, which prevents the magnetic tape retained between the capstan, which is braked by means of the additional brake, and the pressure roller from moving back after braking of the capstan has ceased. However, such a constantly operative additional brake has the drawback that it constitutes a permanent mechanical load to be overcome by the capstan drive and, therefore, requires a proportionately more powerful drive motor for driving the capstan.
In order to minimize such deviations of the distances between successive inclined recording tracks in the longitudinal direction, in an arrangement whose tape drive device comprises a motor-driven capstan disposed downstream the rotationally drivable magnetic head in the longitudinal of the tape, for intermittently driving the magnetic tape, against which capstan the magnetic tape can be pressed by means of a tape pressure roller, it is alternatively possible to couple a so-termed bi-directional tacho-generator to the tape-drive capstan, by means of which, in the case of a backward movement of the magnetic tape as a result of slackening, as explained hereinbefore, a number of tacho-pulses is generated which corresponds to the length of the moved-back tape and which is detected by means of a counting device, the detected number of tacho-pulses being taken into account in driving the magnetic tape when the magnetic tape is accelerated by means of the capstan during a subsequent recording cycle to record a further field signal. The provision of such a bi-directional tacho-generator and such a counting device has the drawback that this requires additional parts which make such an arrangement more expensive.